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The "bispecifics" market improved over the past decade due to the development of many technological platforms including bispecific T cell engagers (BiTEs). The approval of blinatumomab, the most advanced bispecific T-cell engager (BiTE) in clinical trials, can be a significant milestone in the development of bispecific antibodies. Both Chinese hamster ovary (CHO) cells and E. coli strain are considered as the most widely used hosts for the large-scale production of therapeutic monoclonal antibodies. Since both of the economic and qualitative aspects of protein production are important in industry, selection of a suitable protein expression system is very critical. The BsAb gene was cloned into the expression vectors FC550A-1, pcDNA3.1 (+), and PET22b and 6 × His-tagged BsAb then purified on a Ni-NTA chromatography column. Both SDS-PAGE and Western blotting analysis of the purified protein demonstrated that blinatumomab was successfully expressed as a 55 kDa in both expression systems. The antigen-binding properties of blinatumomab were compared in the mammalian system versus Escherichia coli. The results showed that the purified antibody from a mammalian expression system has better binding activity than the one from E. coli host.

Background: IGF-I as a human growth factor produced in Escherichia coli is a single, non-glycosylated, polypeptide chain containing 70 amino acids and having a molecular mass of 7.6 kDa. Up to now, E. coli expression system has been widely used as the host to produce rhIGF-1 with high yields. Acyl Homoserine Lactones (AHLs) are intercellular signaling molecules used in quorum sensing by Gram-negative bacteria. Quorum sensing is a cell density-dependent gene regulation process that allows bacterial cells to express specific genes only when signaling molecules reach the sufficient concentration., Objective: For the first time, this study focuses on the N-hexanoyl-L- Homoserine Lactone (HHL) activity on increasing the cell growth and rh-IGF-1concentration in batch culture of E. coli., Method: The maximum production of rhIGF-I was previously optimized in 32y culture medium at 32°C with 0.05 mM IPTG as inducer and 10 g/l glucose concentration. Under this condition, different amounts of HHL (0.001 µg/ml, 1 µg/ml, and 100µg/ml) were evaluated as an inducer for IGF-1 production., Results: Generally, with increasing of HHL concentration, an increase in dry cell weight (2.45 mg/ml to 4.63 mg/ml) and IGF-I expression level (0.4 mg/ml to 0.77 mg/ml) was observed., Conclusion: HHL or other types of AHLs can be considered as protein production inducer in bacterial expression systems through the quorum sensing pathways., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)